Duszynski / Morrow The Biology and Identification of the Coccidia (Apicomplexa) of Turtles of the World

1. Auflage 2014
ISBN: 978-0-12-801455-4
Verlag: Elsevier Science & Techn.
Format: EPUB
Kopierschutz: 6 - ePub Watermark

E-Book, Englisch, 222 Seiten

The Biology and Identification of the Coccidia (Apicomplexa) of Turtles of the World is an invaluable resource for researchers in protozoology, coccidia, and parasitology, veterinary sciences, animal sciences, zoology, and biology. This first-of-its-kind work offers a taxonomic guide to apicomplexan parasites of turtles that enables easy parasite identification, with a summary of virtually everything known about the biology of each known parasite species. It is an important documentation of this specific area, useful to a broad base of readers, including researchers in biology, parasitology, animal husbandry, diseases of wild and domestic animals, veterinary medicine, and faculty members in universities with graduate programs in these areas. There are about 330 turtle species on Earth; many are endangered, a growing number of species are kept as pets, and some are still used as food by humans. Turtles, like other vertebrate animals have many different kinds of parasites (viruses, bacteria, protozoa, worms, arthropods, and others). Coccidiosis in turtles has prevented large-scale turtle breeding, and represents a serious problem in need of control. This succinct and highly focused book will aid in that effort. - Offers line drawings and photomicrographs of each parasite from each hosts species - Provides methods of identification and treatment - Presents a complete historical rendition of all known publications on coccidia (and their closest relatives) from all turtle species on Earth, and evaluates the scientific and scholarly merit of each - Provides a complete species analysis of the known biology of every coccidian described from turtles - Reviews the most current taxonomy of turtles and their phylogenetic relationships needed to help assess host-specificity and evaluate what little cross-transmission work is available

Dr. Duszynski, is Professor Emeritus Biology and past Chair of the Department of Biology, The University of New Mexico (UNM). He spent 33 years in academia, publishing numerous articles, monographs, and books, secured private, state and federal grants exceeding $8 million, and mentored > 25 masters and doctoral students and numerous undergraduates in his laboratory, before spending 8 years in administration. During his 41 year tenure at UNM, he taught many courses including parasitology, tropical biology and marine invertebrate biology, and took >1000 students to the neotropics (Belize, Jamaica, Mexico). Don has been a Visiting Research Associate Professor, Department of Physiology & Biochemistry, University of Texas Health Science Center, Houston, a Visiting Associate Professor, Department of Microbiology, University of Texas Medical Branch, Galveston, and Visiting Research Scholar, Kyoto University, Japan. Among the honors received are the Distinguished Service Award and the Clark P. Read Mentor Award from the American Society of Parasitologists (ASP), and the Distinguished Alumnus Award from the Department of Biology, Colorado State University.

Autoren/Hrsg.

Duszynski, Donald W.

Morrow, Johnica J.

Inhaltsverzeichnis

1;Front Cover;1
2;The Biology and Identification of the Coccidia (Apicomplexa) of Turtles of the World;4
3;Copyright Page;5
4;Dedication;6
5;Table of Contents;8
6;Preface and Acknowledgments;12
7;1 Introduction;14
7.1;Turtles Are Food, Pets, Lab Animals, and Majestic Creatures;14
7.2;Coccidia in Turtles: Perpetrators, Symptoms, and Disease;16
8;2 Suborder Cryptodira, Hidden-Necked Turtles;20
8.1;Family Chelydridae, Snapping Turtles, 2 Genera, 4 Species;20
8.1.1;Genus Chelydra Schweigger, 1812 (3 Species);20
8.1.1.1;Eimeria chelydrae Ernst, Stewart, Sampson, & Fincher, 1969;20
8.1.1.2;Eimeria filamentifera Wacha & Christiansen, 1979a;22
8.1.1.3;Eimeria serpentina McAllister, Upton, & Trauth, 1990b;23
8.1.1.4;Isospora chelydrae McAllister, Upton, & Trauth, 1990b;25
8.1.2;Genus Macrochelys Gray, 1856 (Monospecific);27
8.1.2.1;Eimeria harlani Upton, McAllister, & Trauth, 1992;27
8.2;Superfamily Testudinoidea;29
8.2.1;Family Emydidae, Pond, Box, Water Turtles, 11 Genera, 50 Species;29
8.2.1.1;Genus Chrysemys Gray, 1844 (Monospecific);29
8.2.1.1.1;Eimeria chrysemydis Deeds & Jahn, 1939;29
8.2.1.1.2;Eimeria marginata (Deeds & Jahn, 1939) Pellérdy, 1974;31
8.2.1.1.3;Eimeria tetradacrutata Wacha & Christiansen, 1976;33
8.2.1.2;Genus Clemmys Ritgen, 1828 (Monospecific);35
8.2.1.3;Genus Deirochelys Latreille, 1801 (Monospecific);35
8.2.1.4;Genus Emydoidea Holbrook, 1838 (Monospecific);35
8.2.1.5;Genus Emys Duméril,1805 (3 Species);35
8.2.1.5.1;Eimeria delagei (Labbé, 1893) Reichenow, 1921;35
8.2.1.5.2;Eimeria emydis Segade, Crespo, Ayres, Cordero, Arias, García–Estévez, Iglesias, & Blanco, 2006;37
8.2.1.5.3;Eimeria gallaeciaensis Segade, Crespo, Ayres, Cordero, Arias, García–Estévez, Iglesias, & Blanco, 2006;38
8.2.1.6;Genus Glyptemys Agassiz, 1857 (2 Species);40
8.2.1.6.1;Eimeria lecontei Upton, McAllister, & Garrett, 1995;40
8.2.1.6.2;Eimeria megalostiedae Wacha & Christiansen, 1974;42
8.2.1.7;Genus Graptemys Agassiz, 1857 (13 Species);44
8.2.1.7.1;Eimeria graptemydos Wacha & Christiansen, 1976;44
8.2.1.7.2;Eimeria juniataensis Pluto & Rothenbacher, 1976;46
8.2.1.7.3;Eimeria pseudogeographica Wacha & Christiansen, 1976;48
8.2.1.8;Genus Malaclemys Gray, 1844 (Monospecific);50
8.2.1.9;Genus Pseudemys Gray, 1856 (8 Species);50
8.2.1.9.1;Eimeria cooteri McAllister & Upton, 1989;50
8.2.1.9.2;Eimeria somervellensis McAllister & Upton, 1992;52
8.2.1.9.3;Eimeria texana McAllister & Upton, 1989b;54
8.2.1.10;Genus Terrapene Merrem, 1820 (4 Species);56
8.2.1.10.1;Eimeria carri Ernst & Forrester, 1973;56
8.2.1.10.2;Eimeria ornata McAllister & Upton, 1989a;58
8.2.1.11;Genus Trachemys Agassiz, 1857 (15 Species);60
8.2.1.11.1;Eimeria pseudemydis Lainson, 1968;60
8.2.1.11.2;Eimeria scriptae Sampson & Ernst, 1969;62
8.2.1.11.3;Eimeria stylosa McAllister & Upton, 1989b;64
8.2.1.11.4;Eimeria trachemydis McAllister & Upton, 1988;66
8.3;Family Testudinidae, Tortoises, 15 Genera, 57 Species;68
8.3.1;Genus Aldabrachelys Loveridge and Williams, 1957 (3 Species);68
8.3.2;Genus Astrochelys Gray, 1873 (2 Species);68
8.3.3;Genus Chelonoidis Fitzgerald, 1835 (13 Species);69
8.3.3.1;Eimeria amazonensis Lainson, Da Silva, Franco, & De Souza, 2008;69
8.3.3.2;Eimeria carajasensis Lainson, Da Silva, Franco, & De Souza, 2008;71
8.3.3.3;Eimeria carbonaria Lainson, Da Silva, Franco, & De Souza, 2008;72
8.3.3.4;Eimeria geochelona Couch, Stone, Duszynski, Snell, & Snell, 1996;74
8.3.3.5;Eimeria iversoni McAllister, Duszynski, & Roberts, 2014;76
8.3.3.6;Eimeria jaboti (Carini, 1942);79
8.3.3.7;Eimeria lainsoni (Lainson et al., 1990) Hurková, Modrý, Koudela, & Šlapeta, 2000;80
8.3.3.8;Eimeria motelo Hurková, Modrý, Koudela, & Šlapeta, 2000;83
8.3.3.9;Eimeria welcomei Lainson, Da Silva, Franco, & De Souza, 2008;85
8.3.3.10;Isospora rodriguesae Lainson, Da Silva, Franco, & De Souza, 2008;87
8.3.4;Genus Chersina Schweigger, 1812 (Monospecific);88
8.3.5;Genus Geochelone Fitzinger, 1835 (3 Species);88
8.3.6;Genus Gopherus Rafinesque, 1832 (5 Species);89
8.3.6.1;Eimeria paynei Ernst, Fincher, & Stewart, 1971;89
8.3.7;Genus Homopus Walbaum, 1782 (5 Species);90
8.3.8;Genus Indotestudo Schlegel & Müller, 1844 (3 Species);90
8.3.9;Genus Kinixys Schweigger, 1812 (8 Species);91
8.3.10;Genus Malacochersus Siebenrock, 1903 (Monospecific);91
8.3.11;Genus Manouria Schlegel & Müller, 1844 (2 Species);91
8.3.12;Genus Psammobates Linnaeus, 1758 (3 Species);91
8.3.13;Genus Pyxis Bell, 1827 (2 Species);91
8.3.14;Genus Stigmochelys Gray, 1873 (Monospecific);91
8.3.15;Genus Testudo Linnaeus, 1758 (5 Species);92
8.3.15.1;Eimeria brodeni Cerruti, 1930;92
8.3.15.2;Isospora testudae Davronov, 1985;93
8.4;Family Geoemydidae (Bataguridae) Asian River, Leaf & Roofed, & Asian Box Turtles, 19 Genera, 70 Species;95
8.4.1;Genus Batagur Gray, 1856 (6 Species);95
8.4.1.1;Eimeria zbatagura Široky & Modrý, 2010;95
8.4.2;Genus Cuora Gray, 1856 (13 Species);96
8.4.2.1;Eimeria hynekprokopi Široky & Modrý, 2010;96
8.4.3;Genus Cyclemys Bell, 1834 (7 Species);98
8.4.3.1;Eimeria palawanensis Široky & Modrý, 2010;98
8.4.3.2;Eimeria petrasi Široky & Modrý, 2010;100
8.4.4;Genus Geoclemys Gray, 1831 (Monospecific);101
8.4.5;Genus Geoemyda Gmelin, 1789 (2 Species);101
8.4.6;Genus Hardella Gray, 1831 (Monospecific);101
8.4.7;Genus Heosemys Gray, 1831 (4 Species);101
8.4.7.1;Eimeria arakanensis Široky & Modrý, 2006;101
8.4.8;Genus Leucocephalon McCord, Iverson, & Boeadi, 1995 (Monospecific);103
8.4.9;Genus Malayemys Lindholm, 1931 (2 Species);103
8.4.9.1;Eimeria surinensis Široky & Modrý, 2010;103
8.4.10;Genus Mauremys Gray, 1869 (9 Species);105
8.4.10.1;Eimeria mitraria (Laveran & Mesnil, 1902) Doflein, 1909;105
8.4.11;Genus Melanochelys Gray, 1834 (2 Species);109
8.4.11.1;Eimeria patta Široky & Modrý, 2005;109
8.4.12;Genus Morenia Duméril & Bibron, 1835 (2 Species);110
8.4.13;Genus Notochelys Gray, 1834 (Monospecific);111
8.4.14;Genus Orlitia Gray, 1873 (Monospecific);111
8.4.15;Genus Pangshura Gray, 1831 (4 Species);111
8.4.15.1;Eimeria pangshurae Široky & Modrý, 2010;111
8.4.15.2;Eimeria kachua Široky & Modrý, 2005;113
8.4.16;Genus Rhinoclemmys Fitzinger, 1835 (9 Species);115
8.4.17;Genus Sacalia Gray, 1870 (2 Species);115
8.4.18;Genus Siebenrockiella Lindholm, 1929 (2 Species);115
8.4.19;Genus Vijayachelys Henderson, 1912 (Monospecific);115
8.5;Family Platysternidae, Big-Headed Turtles, 1 Genus, Monotypic;115
8.5.1;Genus Platysternon Gray, 1831 (Monospecific);115
8.6;Superfamily Trionychoidea;115
8.6.1;Family Carettochelyidae, Pignose Turtles, 1 Genus, Monotypic;115
8.6.1.1;Genus Carettochelys Ramsay, 1886 (Monospecific);115
8.7;Family Trionychidae, Softshell Turtles, 13 Genera, 30 Species;116
8.7.1;Genus Amyda Saint-Hilaire, 1809 (Monospecific);116
8.7.2;Genus Apalone Rafinesque, 1832 (3 Species);116
8.7.2.1;Eimeria amydae Roudabush, 1937;116
8.7.2.2;Eimeria apalone McAllister, Upton, & McCaskill, 1990a;118
8.7.2.3;Eimeria dericksoni Roudabush, 1937;120
8.7.2.4;Eimeria mascoutini Wacha & Christiansen, 1976;122
8.7.2.5;Eimeria pallidus McAllister, Upton, & McCaskill, 1990a;124
8.7.2.6;Eimeria spinifera McAllister, Upton, & McCaskill, 1990a;126
8.7.2.7;Eimeria vesticostieda Wacha & Christiansen, 1977;128
8.7.3;Genus Chitra Gray, 1831 (3 Species);129
8.7.4;Genus Cyclanorbis Gray, 1854 (2 Species);129
8.7.5;Genus Cycloderma Peters, 1854 (2 Species);129
8.7.6;Genus Dogania Gray, 1844 (Monospecific);129
8.7.7;Genus Lissemys (Gray, 1831) Smith, 1931 (2 Species);130
8.7.7.1;Eimeria innominata Kar, 1944;130
8.7.7.2;Eimeria irregularis Kar, 1944;131
8.7.7.3;Eimeria koormae Das Gupta, 1938a, b;132
8.7.7.4;Eimeria légeri (Simond, 1901) Reichenow, 1921;134
8.7.8;Genus Nilssonia Gray, 1831 (5 Species);135
8.7.8.1;Eimeria triangularis Chakravarty & Kar, 1943;135
8.7.8.2;Eimeria trionyxae Chakravarty & Kar, 1943;137
8.7.9;Genus Palea Meylan, 1987 (Monospecific);139
8.7.10;Genus Pelochelys Gray, 1864 (3 Species);139
8.7.11;Genus Pelodiscus Fitzinger, 1835 (4 Species);139
8.7.12;Genus Rafetus Daudin, 1802 (2 Species);139
8.7.13;Genus Trionyx Saint-Hilaire, 1809 (Monospecific);139
8.8;Superfamily Kinosternoidea;139
8.8.1;Family Dermatemydidae, River Turtles, 1 Genus, Monotypic;139
8.8.1.1;Genus Dermatemys Gray, 1847 (Monospecific);139
8.9;Family Kinosternidae, Mud & Musk Turtles, 4 Genera, 25 Species;140
8.9.1;Genus Claudius Cope, 1865 (Monospecific);140
8.9.2;Genus Kinosternon Spix, 1824 (18 Species);140
8.9.2.1;Eimeria lutotestudinis Wacha & Christiansen, 1976;140
8.9.3;Genus Staurotypus Wagler, 1830 (2 Species);142
8.9.4;Genus Sternotherus Gray, 1825 (4 Species);142
8.10;Superfamily Chelonioidea;142
8.10.1;Family Cheloniidae, Sea Turtles, 5 Genera, 6 Species;142
8.10.1.1;Genus Caretta Rafinesque, 1814 (Monospecific);142
8.10.1.1.1;Eimeria caretta Upton, Odell, & Walsh, 1990;142
8.10.1.2;Genus Chelonia Brongniart, 1800 (Monospecific);144
8.10.1.2.1;Caryospora cheloniae Leibovitz, Rebell, & Boucher, 1978;144
8.10.1.3;Genus Eretmochelys Linnaeus, 1766 (Monospecific);149
8.10.1.4;Genus Lepidochelys Fitzinger, 1843 (2 Species);149
8.10.1.5;Genus Natator McCulloch, 1908 (Monospecific);149
8.10.2;Family Dermochelyidae, Leatherback Turtles, 1 Genus, Monotypic;149
8.10.2.1;Genus Dermochelys Blainville, 1816 (Monospecific);149
8.10.3;Discussion and Summary;149
8.10.3.1;Coccidia and Coccidiosis in Cryptodira;150
8.10.3.2;Endogenous Development;152
8.10.3.3;Treatment and Prevention;153
8.10.3.4;Host Specificity in Cryptodira Coccidia;153
8.10.3.5;Prevalence of Eimerians in Cryptodira;154
8.10.3.6;Archiving Biological Specimens for Future Study;155
9;3 Suborder Pleurodira, Side-Necked Turtles;158
9.1;Family Chelidae, Austro-American Sideneck Turtles, 14 genera, 52 species;158
9.1.1;Genus Acanthochelys Gray, 1873 (4 Species);158
9.1.2;Genus Chelodina Fitzinger, 1826 (12 Species);158
9.1.3;Genus Chelus Schneider, 1783 (Monospecific);159
9.1.4;Genus Elseya Gray, 1867 (5 Species);159
9.1.5;Genus Elusor Cann & Legler, 1994 (Monospecific);159
9.1.6;Genus Emydura Bonaparte, 1836 (4 Species);159
9.1.7;Genus Hydromedusa Wagler, 1830 (2 Species);159
9.1.8;Genus Mesoclemmys Gray, 1873 (10 Species);159
9.1.8.1;Eimeria jirkamoraveci Široký et al. (2006a);159
9.1.9;Genus Myuchelys Thomson & Georges, 2009 (5 Species);161
9.1.10;Genus Phrynops Wagler, 1830 (4 Species);161
9.1.11;Genus Platemys Schneider, 1792 (Monospecific);161
9.1.12;Genus Pseudemydura Siebenrock, 1901 (Monospecific);161
9.1.13;Genus Rheodytes Legler & Cann, 1980 (Monospecific);161
9.1.14;Genus Rhinemys Wagler, 1830 (Monospecific);161
9.2;Superfamily Pelomedusoidea;161
9.2.1;Family Pelomedusidae, Afro-American Sideneck Turtles, 2 Genera, 19 Species;161
9.2.1.1;Genus Pelomedusa Lacépède, 1788 (Monospecific);161
9.2.1.1.1;Eimeria lokuma Široký et al. (2006b);161
9.2.1.2;Genus Pelusios Wagler, 1830 (18 Species);163
9.3;Family Podocnemididae, Madagascan Big Headed, and American Sideneck River Turtles, 3 Genera, 8 Species;163
9.3.1;Genus Erymnochelys Grandidier, 1867 (Monospecific);163
9.3.2;Genus Peltocephalus Duméril & Bibron, 1835 (Monospecific);163
9.3.2.1;Eimeria peltocephali Lainson & Naiff (1998);163
9.3.3;Genus Podocnemis Wagler, 1830 (6 Species);165
9.3.3.1;Eimeria lagunculata Lainson et al. (1990);165
9.3.3.2;Eimeria mammiformis Lainson et al. (1990);168
9.3.3.3;Eimeria podocnemis Lainson et al. (1990);170
9.4;Discussion and Summary;171
10;4 Cryptosporidium, Sarcocystis, Toxoplasma in Turtles;174
10.1;Cryptosporidium in Turtles;174
10.2;Sarcocystis in Turtles;176
10.2.1;Sarcocystis kinosterni Lainson & Shaw, 1972;176
10.3;Toxoplasma in Turtles;177
11;5 Species Inquirendae in Turtles;180
11.1;Species Inquirendae (28);180
11.1.1;Coccidium sp. of Jacobson et al., 1994;180
11.1.2;Coccidium sp. of Garner et al., 1998;180
11.1.3;Coccidium sp. of Garner et al., 2006;181
11.1.4;Coccidium sp. of Innis et al., 2007;182
11.1.5;Caryospora sp. of Greiner, 2003;182
11.1.6;Cryptosporidium sp. of Bourdeau, 1988, 1989;183
11.1.7;Cryptosporidium sp. of Funk, 1987;183
11.1.8;Cryptosporidium sp. 1 of Graczyk & Cranfield, 1998;183
11.1.9;Cryptosporidium sp. 2 of Graczyk & Cranfield, 1998;183
11.1.10;Cryptosporidium sp. of Graczyk et al., 1997;184
11.1.11;Cryptosporidium sp. of Graczyk et al., 1998;184
11.1.12;Cryptosporidium sp. of Häfeli & Zwart, 2000;184
11.1.13;Cryptosporidium sp. of Heuschele et al., 1986;185
11.1.14;Cryptosporidium sp. of Xiao et al., 2004;185
11.1.15;Eimeria sp. of Bone, 1975 vide Wacha & Christiansen, 1976;185
11.1.16;Eimeria sp. of McAllister et al., 1994;186
11.1.16.1;Eimeria sp. of Wacha & Christiansen, 1976;186
11.1.17;Eimeria sp. 1 of Wacha & Christiansen, 1980;187
11.1.18;Eimeria sp. 2 of Wacha & Christiansen, 1980;187
11.1.18.1;Mantonella hammondi Wacha & Christiansen, 1974b;188
11.1.19;Sarcocystis sp. of Keymer, 1978a;188
11.1.20;Sarcocystis sp. of Keymer, 1978b;188
11.1.21;Sarcocystis spp. of Meshkov, 1975;189
11.1.22;Sarcocystis sp. 1 of Weishaar et al., 1988;189
11.1.23;Sarcocystis sp. 2 of Weishaar et al., 1988;189
11.1.24;Sarcocystis sp. 3 of Weishaar et al., 1988;189
11.1.25;Sarcocystis sp. 4 of Weishaar et al., 1988;190
11.1.26;Sarcocystis sp. 5 of Weishaar et al., 1988;190
12;6 Discussion and Summary;192
12.1;Biodiversity;192
12.2;Variety of Oocyst Structures and Shape;193
12.3;Host Specificity;195
12.4;Pathology;196
12.5;Epidemiology;197
12.6;Treatment and Control;198
12.7;Archiving Biological Specimens;199
12.8;Closing Remarks;200
13;Tables;202
14;Literature Cited;216

Leseproben

Chapter 1 Introduction
This chapter notes the importance of turtles in the lives of humans (food, lab animals, and pets) and the majestic nature of these slow moving creatures as denizens of our earthly environment. It briefly discusses the physical features of turtles, their habitats, and how to distinguish between the two major groups (suborders) of extant turtles. We mention various ways in which humans have used and continue to use turtles and note that at least 50% of all turtle taxa may be nearing the brink of extinction. We identify and discuss the three protist families and five of their genera that are found most commonly in turtles; these include: Eimeriidae (Eimeria, Isospora, Caryospora spp.), Sarcocystidae (Sarcocystis spp.), and Cryptosporididae (Cryptosporidium sp.). The general biology, life cycles, and morphology of the stages used in identification of these groups are discussed. Finally, we mention that the order Testudines (turtles) consists of 2 suborders, 14 families with 92 genera that comprise 328 species. Coccidia have been described from 10 of the 14 (71%) families, 32 of the 92 (35%) genera, and only 64 of the 328 (19.5%) turtle species. Keywords
Turtles; food; pets; lab animals; coccidia; species; taxonomy; systematics; epidemiology of disease; Eimeria; Isospora; Caryospora; Sarcocystis; Cryptosporidium This treatise on coccidia species known from turtles has several predecessors including, The Coccidia of Snakes of the World (Duszynski & Upton, 2009) and The Biology and Identification of the Coccidia of Rabbits of the World (Duszynski & Couch, 2013). Like the others, it is intended to be the most comprehensive discourse, to date, describing the structural and biological knowledge of all coccidian parasites that infect turtles. These protists (Phylum Apicomplexa) seem relatively common in turtles and are represented by about 71 species that fit taxonomically into five genera in three families that include Cryptosporidiidae Léger, 1911 (Cryptosporidium), Eimeriidae Minchin, 1903 (Caryospora, Eimeria, Isospora), and Sarcocystidae Poche, 1913 (Sarcocystis). An overview of the general biology, taxonomy, life cycles, and numbers of species of eimeriid and cryptosporid coccidia from wild mammals was published a decade ago (Duszynski & Upton, 2001), and monographic works on the coccidia of certain selected vertebrate groups also are available including: Amphibia (Duszynski et al., 2007); Chiroptera (Duszynski, 2002); Insectivora (Duszynski & Upton, 2000); Marmotine squirrels (Rodentia) (Wilber et al., 1998); and Primates and Scandentia (Duszynski et al., 1999). No such review exists for the coccidia of turtles. Here we strive to resolve that void because turtles have a long and important history shared with humans and many (>50%) of their extant species are threatened with extinction as human populations continue to increase on Earth. Turtles are Food, Pets, Lab Animals, and Majestic Creatures
Almost everyone can recognize turtles because of their shells. These are remarkable and distinguishing structures that enclose the body of the entire animal in a bony case that only opens at the front and the rear. The shell, of course, helps to protect them from natural enemies, but it also has limited their morphological diversity; there are terrestrial and aquatic turtles, but no turtles can climb (arboreal) or fly. The habits of turtles often may be deduced by the appearance of their shells. Terrestrial turtles (e.g., tortoises and box turtles) generally have high, domed shells and stout limbs, whereas aquatic turtles usually have relatively flat shells (for less resistance in water) and webbed feet. However, some aquatic forms (e.g., mud and musk turtles) spend more time walking on the bottom than they do swimming, and these may have more distinct dome-shaped shells than those that swim quickly to capture prey and avoid predation. Other aquatic turtles have even more specialized soft shells that lack a bony layer, while still others have greatly reduced dermal bones and the stiff dermal scales, which have been replaced by a flexible covering of skin (Pough et al., 2004). Sometimes the term Testudines is used by biologists to encompass all turtles, including both their extinct ancestors and the two major groups of living (extant) turtles (Cryptodira and Pleurodira) and their descendants. The term Chelonia is widely used for the extant clades only. All extant turtles belong to one of these two groups (clades) that are taxonomically referred to as suborders. The Cryptodira and the Pleurodira are distinguished from each other by the way they retract their necks. Turtles placed into the Cryptodira retract their neck in a vertical plane, whereas members of the Pleurodira (side-necked turtles) retract their necks in a horizontal or sideway plane. Nonetheless, because of the many unique structural features (shell, skeleton, skull bones, others), the monophyly of turtles has never been in serious question by herpetologists (Pough et al., 2004). Turtles and humans share a long association, with the former being used as gourmet food, as subjects in both oriental and traditional medicine and contemporary medical research, their fat as a base for cosmetics, their shells as jewelry and, of course, millions of humans have them as pets. There are currently 328 distinct turtle species recognized by herpetologists. However, the number of turtle taxa becomes more complex because 56 of those species are polytypic (have more than one immediately subordinate taxon), which introduces 124 additional recognized subspecies (Rhodin et al., 2010). Thus, herpetologists now recognize 452 taxa of modern tortoises and turtles, of which 10 taxa (8 species, 2 subspecies) are now considered extinct. In their 2010 update on turtles of the world, Rhodin et al. (2010) listed 156 of the 328 species (48%) as Threatened, with 90 (27%) as Critically Endangered or Endangered on the International Union for the Conservations of Nature (IUCN) Red List. When they included Extinct-in-the-Wild and Extinct species, their data suggested that at least 50% of all modern turtle and tortoise species either are already extinct or threatened with extinction. In other words, turtles are threatened with extinction at a much higher risk than almost all other vertebrate species. The threats that turtles face include, but are not limited to, long-term unsustainable exploitation, habitat destruction, overharvesting for consumption, and the international pet trade. Coccidia in Turtles: Perpetrators, Symptoms, and Disease
This review primarily is concerned with the eimeriid coccidia found in turtles, but mention also will be made of genera and species in two other protist families, Sarcocystidae (Sarcocystis, Toxoplasma spp.) and Cryptosporididae (Cryptosporidium sp.). All species in these genera are single-celled, intracellular, eukaryotic parasites (Protozoa: Apicomplexa) that pass a highly resistant propagule, the oocyst, in the feces of their definitive host. Most of these parasites develop in the epithelial cells of the gastrointestinal tract, but a few develop in other tissues and organs. Their life cycles are complex and include both asexual reproduction (merogony), which can produce extremely high numbers of individuals, and sexual reproduction (gamogony) that allows genetic recombination. After fertilization takes place and oocyst wall formation and development is completed, the oocyst leaves the host epithelial cell, destroying it, and usually (but not always) needs a period of time outside the host to undergo its final developmental process, sporogony. After sporogony, the oocyst becomes infective to the next host that may encounter this stage and ingest it. The majority of the species summarized in our review are in the Eimeriidae (Eimeria, Isospora, Caryospora spp.). As best we know, all of these parasites are homoxenous in their development; that is, they have a single host, direct (host-to-host) life cycle. Cryptosporidium species also have direct life cycles, but Sarcocystis species are heteroxenous in that they require two hosts, a definitive host that discharges the oocysts, and an intermediate host that contains infective tissue stages/cysts that must be eaten by the definitive host to complete the life cycle. Toxoplasma species can be either homoxenous (only in felids) or heteroxenous in their development. Even though their intracellular development kills their hosts’ epithelial or endothelial cells, most coccidia are considered nonpathogenic; however, as we will learn in the following chapters, we know so little about the complete development and life cycles of the majority of known species, that we really don’t know what levels of pathogenicity may exist in turtle coccidia. Still, there are exceptions to these gaps in our understanding, as noted in later chapters. The most distinguishing feature of the coccidian life cycle that allows diagnosis, for example, by a veterinarian, is the structure of the sporulated oocyst; oocysts of most coccidians (e.g., Caryospora, Eimeria, Isospora, Toxoplasma spp.) leave their host unsporulated and need molecular oxygen and usually a temperature different than the body temperature of their host to undergo sporulation. A few, however, like the Cryptosporidium and Sarcocystis species, have completely sporulated oocysts and/or sporocysts that leave their host in its feces. In the...